(CNN) – Here’s a little-known fact: Under current law, it’s possible to hold a patent on a piece of human DNA, otherwise known as a gene.

Companies that have acquired patents for genes have specific rights to their use, which may include diagnostic tests based on those genes, as well as future mutations that are discovered.

In a new lawsuit, the American Civil Liberties Union alleges that the policy is unconstitutional.

The targets of the lawsuit, Myriad Genetics and the University of Utah Research Foundation, hold patents to BRCA1 and BRCA2, the genes responsible for many cases of hereditary breast and ovarian cancers.

The U.S. Patent and Trademark Office is also named in the suit.

The lawsuit asserts that the patents prevent some people from accessing medical screening for BRCA1 and BRCA2. It also challenges the general patentability of genes, which has been legal since 1980. That year, in Diamond v. Chakrabarty, the Supreme Court found in favor of Ananda Mohan Chakrabarty, who used bacteria to engineer a microbe that dissolves oil. Video Watch Dr. Gupta explain the lawsuit »